1. Field of the Invention
The present invention relates to a substrate treatment apparatus for treating a substrate such as a semiconductor wafer, a substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magnetooptical disk or a substrate for a photomask, for example.
2. Description of Related Art
In the process of manufacturing a semiconductor device or a liquid crystal display include a resist removing treatment for removing (separating) a resist from the surface of a substrate such as a semiconductor wafer or a glass substrate for a liquid display panel with an SPM (a sulfuric acid/hydrogen peroxide mixture) and a cleaning treatment for removing a natural oxide film from the substrate with hydrofluoric acid (HF).
A single substrate treatment apparatus treating substrates one by one may be employed for such chemical solution treatments. The single substrate treatment apparatus includes a spin chuck rotating each substrate while generally horizontally holding the same, a bottomed cylindrical cup storing the spin chuck, a chemical solution nozzle for supplying chemical solutions to the substrate and a DIW nozzle for supplying DIW (deionized water) to the substrate in a treatment chamber comparted by partitions.
In each chemical solution treatment, the chemical solution is supplied from the chemical solution nozzle to the surface of the substrate rotated by the spin chuck. The chemical solution supplied onto the surface of the substrate spreads on the entire region of the surface of the substrate due to centrifugal force resulting from the rotation of the substrate. After the supply of the chemical solution is stopped, the DIW is supplied from the DIW nozzle to the surface of the substrate, to rinse the chemical solution adhering to the substrate with the DIW. After the supply of the DIW is stopped, the DIW adhering to the substrate is drained and removed by high-speed rotation of the substrate. Thus, the substrate is dried, and the serial chemical solution treatment is completed.
The spin chuck is stored in the cup, whereby the chemical solution splashing from the substrate upon supply thereto is received by the cup and prevented from splashing out of the cup. When a mist of a chemical solution flies due to an upward current and leaks out of the cup from an upper opening of the cup in the chemical solution treatment, however, the inner wall of the treatment chamber and members in the treatment chamber are contaminated with the mist of the chemical solution. When dried in the treatment chamber, the mist of the chemical solution may form particles floating in the atmosphere, to contaminate subsequently treated substrates. Therefore, a structure obtained by providing an FFU (fan filter unit) on the top face of the treatment chamber and forming an exhaust port in the bottom portion of the cup is employed (refer to Japanese Unexamined Patent Publication No. 2006-286834). According to the structure, exhaustion can be performed through the exhaust port while supplying a downflow of clean air from the FFU toward the substrate. Consequently, a downflow toward the exhaust port can be formed around the substrate, and the mist of the chemical solution can be prevented from flying due to the downflow.
The “mist” denotes vapor or droplets of a specific substance, capable of floating or splashing in the air.
When the structure is employed, however, turbulence may be formed around the substrate and a mist of a chemical solution may fly in the chemical solution treatment if air supply from the FFU and exhaustion from the exhaust port are unbalanced. It is difficult to keep the air supply and the exhaustion well-balanced, and hence the mist of the chemical solution frequently floats around the spin chuck after termination of the chemical solution treatment.
The drying treatment is performed by rotating the substrate on the spin chuck, similarly to the chemical solution treatment. Therefore, the mist of the chemical solution floating around the spin chuck may form particles, to contaminate the substrate in the process of the drying treatment.
Further, the chemical solution splashing from the substrate to be received by the cup is dried and crystallized on the wall surface of the cup, and the dried chemical solution may form particles to contaminate the substrate rotated on the spin chuck. While the cup is periodically cleaned for preventing drying of the chemical solution on the wall surface of the cup in order to prevent such contamination, it is difficult to completely remove the chemical solution. In other words, a bad influence exerted by the dried chemical solution adhering to the cup cannot be avoided so far as the drying treatment is performed in the cup (or around the cup).